Release cause for transition from connected state

ABSTRACT

Systems, methods, and apparatus for handling communications relating to suspending a user equipment in a radio access network (RAN) are disclosed. An example method includes the user equipment receiving a radio resource control (RRC) release message from a network node. The user equipment determines that the RRC release message includes a suspend configuration field. The user equipment applies delta signalling corresponding to a suspend configuration indicated by the suspend configuration field and transitions to an inactive state.

This application is a continuation of U.S. application Ser. No.16/964,301, filed Jul. 23, 2020, which is a 371 of InternationalApplication No. PCT/IB2019/053876, filed May 10, 2019, which claims thebenefit of and priority to U.S. Provisional Patent Application No.62/669,804, filed May 10, 2018, entitled “RELEASE CAUSE FOR TRANSITIONFROM CONNECTED STATE,” the disclosures of which are hereby incorporatedherein by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates generally to communications, such as incellular networks, and more particularly to methods, user equipments,and network nodes for handling communications corresponding tosuspending a user equipment in a radio access network (RAN).

BACKGROUND

In the new 5G standard, the system and architecture for 5G and variousstate machines are described. One example of a “state machine” is theconnection management state model or CM-state model, described in 3GPPTS 23.501. Generally, connection management includes functions forestablishing and releasing signaling connections between a UE and corenetwork node. For 5G, this core network node is called an Access andMobility Management Function (AMF). A signaling connection over an N1interface (between a UE and AMF) is used to enable Non-Access-Stratum(NAS) signaling exchange between the UE and the core network. Itcomprises both the AN (Access Node) signaling connection between the UEand the AN, and an N2 connection, between the AN and the AMF.

In the 5G architecture, there are two CM-states defined, CM-IDLE andCM-CONNECTED. A UE in CM-IDLE has no NAS signaling connectionestablished over N1 to the AMF and in this CM-state, the UE performscell selection/reselection and PLMN selection. In addition, there is noAN signaling connection or N2/N3 connections for a UE in idle state. Ifthe UE is registered to the network and in CM-IDLE, it may listen to andrespond to paging messages from the network. This means that in CM-IDLEthe UE is still reachable. If initiated by user/UE, the UE may alsoperform a service request procedure.

A UE in CM-CONNECTED is a UE that has established an AN signalingconnection between the UE and the AN has entered the RRC_CONNECTED stateover 3GPP access. Over this connection, the UE can transmit an initialNAS message (for example, a service request) and this message initiatesthe transition from CM-IDLE to CM-CONNECTED in the AMF. It is alsorealized that CM-CONNECTED uses an N2 connection, between the AN and theAMF. The reception of an initial N2 message (e.g., N2 Initial UEmessage) initiates the transition for AMF from CM-IDLE to theCM-CONNECTED state.

In the CM-CONNECTED state, the UE can transmit data, and is ready toenter CM-IDLE, whenever the AN signaling connection is released. The AMFenters CM-IDLE whenever the logical N1 signaling connection and the N3user plane connection are released.

Similar to the AMF, there is also a state model in the AN, the accessnetwork, which is described in detail in the 38.331 RRC specifications.Although, “gNB” generally refers to the access network node, other nodetypes are contemplated, including ng-eNB and an eNB node types. The term“gNB” shall thus be considered as merely an example. From the AS (AccessStratum) perspective, UEs can either be in the RRC_CONNECTED,RRC_INACTIVE or RRC_IDLE states. The mapping between the different statemachines, the one in the AN and the one in AMF, is such thatCM-CONNECTED can map to either RRC_CONNECTED or RRC_INACTIVE—whileCM-IDLE always maps to RRC_IDLE.

A UE is either in RRC_CONNECTED state or in RRC_INACTIVE state when anRRC connection has been established. If this is not the case, i.e. noRRC connection is established, the UE is in RRC_IDLE state. Thesedifferent states are further described in 3GPP TS 38.331.

In RRC_IDLE, the UE is configured to listen to a paging channel atcertain occasions and it performs cell (re)selection procedures andlisten to system information. In RRC_INACTIVE, the UE is also listeningto paging channel and does cell (re)selection procedures, but inaddition, it also maintains a configuration and the configuration isalso kept on the network side, such that when needed (e.g., when dataarrives to the UE), it doesn't require a complete setup procedure tostart transmitting data.

In RRC_CONNECTED, there is transfer of data to or from the UE and thenetwork controls the mobility. This means that the network controls whenthe UE should handover to other cells. In connected, the UE stillmonitors the paging channel and it monitors control channels that areassociated with whether there is data for the UE or not. It provideschannel quality and feedback information to the network and it performsneighbouring cell measurement and reports these measurements to thenetwork.

When a UE is in CM-CONNECTED and RRC_INACTIVE the following applies:

-   -   UE reachability is managed by the RAN, with assistance        information from core network;    -   UE paging is managed by the RAN;    -   UE monitors for paging with UE's CN (5G S-TMSI) and a RAN        identifier (I-RNTI).

The AMF, based on network configuration may provide assistanceinformation to the NG-RAN, to assist the NG-RAN's decision whether theUE can be sent to RRC inactive state. RRC inactive assistanceinformation can, for example, include:

-   -   UE specific DRX values;    -   the Registration Area provided to the UE, sometimes referred to        as TAI-list (TrackingAreaIdentifier List) below;    -   Periodic Registration Update timer;    -   If the AMF has enabled MICO mode for the UE, an indication that        the UE is in MICO mode;    -   Information from the UE permanent identifier, as defined in TS        38.304 [50], that allows the RAN to calculate the UE's RAN        paging occasions.

The RRC inactive assistance information mentioned above is provided bythe AMF during N2 activation with the (new) serving NG-RAN node (i.e.during Registration, Service Request, handover) to assist the NG-RAN'sdecision whether the UE can be sent to an RRC inactive state. The RRCinactive state is part of RRC state machine, and it is up to the RAN todetermine the conditions to enter the RRC inactive state. If any of theparameters included in the RRC inactive assistance information changesas the result of NAS procedure, the AMF shall update the RRC inactiveassistance information to the NG-RAN node.

The state of the N2 and N3 reference points are not changed by the UEentering CM-CONNECTED with RRC inactive state. A UE in RRC inactivestate is aware of the RAN Notification area (RNA).

RNA Configuration in RRC_INACTIVE

A UE in the RRC_INACTIVE state can be configured with an RNA (RAN-basedNotification Area), where:

-   -   the RNA can cover a single or multiple cells, and can be smaller        than CN Registration area;    -   a RAN-based notification area update (RNAU) is periodically sent        by the UE and is also sent when the cell reselection procedure        of the UE selects a cell that does not belong to the configured        RNA.

There are several different alternatives on how the RNA can beconfigured:

-   -   List of cells:    -   A UE is provided an explicit list of cells (one or more) that        constitute the RNA.    -   List of RAN areas:    -   A UE is provided (at least one) RAN area ID, where a RAN area is        a subset of a CN Tracking Area;    -   A cell broadcasts (at least one) RAN area ID in the system        information so that a UE knows which area the cell belongs to.    -   List of TAI (Tracking Area Identifiers).

In CM-IDLE, it is the core network that is in charge of UE reachabilityand the core network does this through configuring a CN registrationarea that is defined by a set of Tracking Areas (TA)'s. The UE isconfigured with the CN registration area through a list of Tracking AreaIdentifiers, TAI's, and this CN Registration area is referred to as“TAI-list”.

At transition into CM-CONNECTED with RRC inactive state, the NG-RANconfigures the UE with a periodic RAN Notification Area Update timertaking into account the value of the Periodic Registration Update timervalue indicated in the RRC Inactive Assistance Information, and uses aguard timer with a value longer than the RAN Notification Area Updatetimer value provided to the UE.

If the periodic RAN Notification Area Update guard timer expires in RAN,the RAN can initiate the AN Release procedure as specified in TS 23.502[3].

When the UE is in CM-CONNECTED with RRC inactive state, the UE performsPLMN selection procedures as defined in TS 23.122 [17] for CM-IDLE.

When the UE is CM-CONNECTED with RRC Inactive state, the UE may resumethe RRC connection due to:

-   -   Uplink data pending;    -   Mobile initiated NAS signalling procedure;    -   As a response to RAN paging;    -   Notifying the network that it has left the RAN Notification        area;    -   Upon periodic RAN update timer expiration.

When Resuming, UE will include an identifier to the network that willinform the network node about where the UE context describing thespecifics of the UE, e.g., bearers, tracking area, slices, securitycredentials/keys, and so forth) such that resuming will bring the UE toan RRC_CONNECTED configuration similar to when it was resumed. TheIdentifier pointing to the UE Context is called I-RNTI, Inactive RadioNetwork Temporary Identifier. In connection to when the UE is suspended,i.e., it is transitioned from RRC_CONNECTED to RRC_INACTIVE, it isprovided with an I-RNTI from the network. The network allocates anI-RNTI when transitioning UE to RRC_INACTIVE and the I-RNTI is used toidentify the UE context, i.e., as an identifier of the details storedabout the UE in the network while in RRC_INACTIVE.

Much of the behaviour in RRC_INACTIVE is tightly coupled with theability to connect a radio network to the 5G core network or to connectit to an AMF. Even though there is no new state in the AMF (it is stillonly CM CONNECTED and CM IDLE) there is still a need for the AMF to know(e.g., to provide the assistance information).

Further, as it is possible to connect the LTE/EUTRA radio network to anAMF or to the 5G core network, all the procedures that are specified forthe new radio (NR) should also apply for when the long term evolution(LTE) radio access is connected to 5GC (5G core network). Thus, there isa need to adapt the procedures, such as the RRC protocols, to the LTEradio protocols.

In an LTE standard, there is a procedure for suspending the UE definedin 36.331, which was introduced in Release 13. This is applicable forwhen LTE connects to EPC, with an MME node directly connected to theeNB, to the core network defined for E-UTRA, as described, e.g., in 3GPPTS 23.401, including NAS procedures described in 3GPP TS 24.301. In away this suspend procedure applicable for nodes connecting to EPC sharessome similarities with RRC_INACTIVE in that the AS context is storedsuch that a UE can send a resume request and information from lastsession can be retrieved and doesn't have to be signaled again. Inanother and very important way, it is not the same as RRC_INACTIVE, asthe core network is in a state corresponding to CM-IDLE, i.e., it doesnot consider the UE connected. This means that it is the core networkthat does the paging when a UE is suspended in a cell that connects toEPC.

The way to indicate to the UE that it shall be suspended in EPC is tosend a release message with a suspend indication, which is modeled as acause value that means the UE goes to suspend. The specification forthis message is described further in 3GPP TS 36.331. It can be notedfrom the specification that there is a specific release cause defined tosuspend the UE such that it can later on be resumed and AS informationis stored. This is indicated as “rrc-Suspend-v1320”. If the UE issuspended, there is also a resumeIdentity included, which the UE caninclude if it wants to resume and allow the network to retrieveinformation about the UE.

SUMMARY

The examples described in the present disclosure can be used to improvesignalling relating to suspending a UE, resulting in lower overhead,power savings, and improved efficiency. Other advantages may be readilyapparent to one having skill in the art. Certain embodiments may havenone, some, or all of the recited advantages.

A system of one or more computers can be configured to performparticular operations or actions by virtue of having software, firmware,hardware, or a combination of them installed on the system that inoperation causes or cause the system to perform the actions. One or morecomputer programs can be configured to perform particular operations oractions by virtue of including instructions that, when executed by dataprocessing apparatus, cause the apparatus to perform the actions. Onegeneral aspect includes a method performed by a user equipment forhandling communications from one or more network nodes in a radio accessnetwork (RAN), the method including: receiving, by a user equipment thatis operating in a connected state, an RRC release message from a networknode. The method also includes determining, based on an indication inthe RRC release message, whether to suspend the user equipment to aninactive state or an idle state, the indication including a presence orabsence a suspend configuration field in the RRC release message. Themethod also includes responsive to determining that the indication is tosuspend to an inactive state, transitioning the user equipment to theinactive state.

One general aspect includes a method performed by a network node forproviding communications to a user equipment in a radio access network(RAN), the method including: providing, to the user equipment that isoperating in a connected state, an RRC Release message. The method alsoincludes triggering, based on an indication in the RRC Release message,a suspension of the user equipment to an inactive state or an idlestate, the indication including a presence or absence a suspendconfiguration field in the RRC release message. The method also includescausing, responsive to the indication being to suspend to an inactivestate, the user equipment to transition to the inactive state.

Other embodiments of the above aspects include corresponding computersystems, apparatus, and computer programs recorded on one or morecomputer storage devices, each configured to perform the actions of themethods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow diagram illustrating a method for transitioning a userequipment to an inactive state, according to some examples.

FIG. 2 is a flow diagram illustrating a method for transitioning a userequipment to an inactive state, including an additional cause valueindication, according to some examples.

FIG. 3 is a flow diagram illustrating a method performed by a userequipment for transitioning to an inactive state or an idle state,according to some examples.

FIG. 4 is a flow diagram illustrating a method performed by a networknode for transitioning a user equipment to an inactive state or an idlestate, according to some examples.

FIG. 5 is a block diagram illustrating a wireless network, according tosome examples.

DETAILED DESCRIPTION

Some of the embodiments contemplated herein will now be described morefully with reference to the accompanying drawings. Other embodiments,however, are contained within the scope of the subject matter disclosedherein, the disclosed subject matter should not be construed as limitedto only the embodiments set forth herein; rather, these embodiments areprovided by way of example to convey the scope of the subject matter tothose skilled in the art.

In a number of ways, the suspend procedure for LTE is similar to what isgoing to be introduced for NR and for connecting to the new network withan AMF node. In the case of transitioning to RRC_INACTIVE, there is alsoa suspend procedure needed, to signal to the UE that it should enter anRRC_INACTIVE state. In NR, for a release message with a suspendindication, there is no release cause included. The inclusion of asuspend configuration in itself could indicate to the UE that therelease message means release-to-RRC_INACTIVE. Without the suspendconfiguration, the release message means Release to RRC_IDLE. In someexamples, the suspend configuration is indicated by a field such asRRC-InactiveConfig or suspendConf.

In NR, there is no legacy to consider. This means that a suspend in NRis always a suspend to RRC_INACTIVE. This makes it possible to go thinon distinguishing different cause values. When a corresponding suspendmechanism should be introduced in LTE when connecting to 5GC, which isan existing message, there are advantages in clearly differentiatingbetween the different suspend to an idle state (RRC_IDLE, which isalready supported in LTE) and suspend to an inactive state(RRC_INACTIVE), which is new for LTE.

In addition to the above, it is also desired in NR to consider asituation when a release message only should include information that isnew, i.e., that is changed from previous signaling (i.e., deltasignaling of the RRC release message or at least the suspendconfiguration). In this situation there may be a confusion in what thesuspend configuration in the release message means. For example, if arelease message without any suspend configuration indication is receivedby a UE, it would be ambiguous whether the UE shall release to an idlestate, or would it mean that it is a suspend to an inactive with nochanges in the suspend configuration.

There currently exist certain challenge(s). In more detail, there is aneed to be able to differentiate between suspend to an idle state andsuspend to an inactive state when a release message is used to suspendUE. This is particularly important for LTE, as in LTE, there are twodifferent suspend mechanisms

For NR and for LTE connected to 5GC, there is also a need to distinguishbetween a release message that suspend a UE to RRC_INACTIVE with nochanges in suspendConfig and a release message that suspends a UE toRRC_IDLE.

Certain aspects of the present disclosure and their embodiments mayprovide solutions to these or other challenges.

In one aspect, a release cause value is included in the RRC releasemessage in LTE to indicate to a UE that the release is due to transitionto RRC_INACTIVE. The indication can be implicit or explicit to enablethe UE to distinguish between a suspension to an idle state or to aninactive state. Different embodiments describe the different types ofindications, for example the presence of one or two specific parametersonly relevant for a given state like inactive, etc. Although we say thisis about LTE the fundamental aspect that can be applicable to any RAT(like NR) is the distinction between is the suspend to idle (LTE Release13 solution) or suspend to inactive, where some actions performed arecommon, but some are specific for each solution.

In another aspect, a release cause included in the RRC message when thesuspend to inactive is signaled in LTE RRC Connection Release message isdifferent than the release cause used for suspending an LTE UE to idle.UE actions upon suspending may be distinguished based on thatindication. For example, when suspending to inactive the UE apply someexclusive parameters such as RAN paging configuration, RNA updateconfigurations, periodic RNA timer, etc.

In another aspect, the release cause included is implicit, i.e., byincluding a new identifier value in suspendConfig that is valid forrelease to RRC_INACTIVE.

In another aspect, a release cause is included also in the releasemessage when signaled in NR, such that it can allow for not includingsuspendConfig unless there are changes to the configuration that are tobe signaled.

In another aspect, including an explicit or implicit identifier willallow delta-signaling of RRC_INACTIVE-related information that wouldotherwise not be possible, if there weren't a release cause.

In another aspect, the AS and NAS layers in the UE interact so that therelease cause distinguishing the UE to enter RRC_IDLE or RRC_INACTIVE isprovided from the lower layers to the upper layers upon the reception ofthe RRC Release message so that the upper layers can perform anunambiguous transition from a connected state to an idle state or, inthe case of the indication to enter an inactive state, to remain in aconnected state from an upper layer perspective.

There are, proposed herein, various embodiments which address one ormore of the issues disclosed herein, and may provide one or more of thefollowing technical advantage(s).

In some embodiments, the techniques described herein allow for bothdifferentiation of suspend in LTE connecting to both EPC and 5GC. Insome embodiments, the techniques described herein allow for indicatingto a UE if the release message is a release to RRC_INACTIVE or a releaseto RRC_IDLE.

Moreover, by including a release cause also in NR, the techniques allowdelta-signaling of the configuration parameters that are applicable forRRC_INACTIVE state. The release cause offers the advantage of notincluding new suspendConfig values where the values are not changed, andthus includes signal parameters in the suspendConfig only when they arechanged. This will save in signaling, resulting in lower overhead, powersavings, and improved efficiency, among other things.

FIG. 1 is a flow diagram illustrating an example method fortransitioning a user equipment to an RRC_INACTIVE state. For example,the method illustrates signaling in NR connected to 5GC, according tosome embodiments.

Step 100, the UE receives a release message from the network. In thisexample the UE is in RRC_CONNECTED and is about to be released. Thereasons for releasing a UE in RRC_CONNECTED can vary. It can for examplebe due to inactivity, or due to that there is no more data to sendand/or receive.

In step 102, the UE reads and interprets the release message. If thereis an indication in the release message that the release refers to asuspend to RRC_INACTIVE, then the UE proceeds to step 106. Thatindication can be a release-cause ‘suspend’. If, on the other hand, therelease message does not include such an indication (e.g. includeanother release cause instead), the release message is not about Releaseto RRC_INACTIVE, but it is rather sent for other purposes, this isillustrated in the figure as 104. In some examples, the release is toRRC_IDLE but there could also be other situations when a release messagemay mean something different. In this embodiment, focus is on whetherthe indication to RRC_INACTIVE is included.

The indication helps the UE to apply delta signalling to the suspendconfiguration. If that indication does not exist, the absence of thesuspend configuration field could be interpreted as an indication fromthe network to move the UE to RRC_IDLE. However, based on thatindication, the UE knows that the absence of the suspend configurationfield means that the UE can apply delta signalling to a previouslystored suspend configuration. In other words, the UE can enterRRC_INACTIVE and use the stored suspend configuration when enteringRRC_INACTIVE.

If included, in step 106, the UE checks for a new suspendConfig andreads any new potential suspendConfig information that relates to howthe UE should behave/be configured in RRC_INACTIVE state.

If suspendConfig information is included, the UE replaces any storedsuspendConfig information. For any suspendConfig information notincluded in the release message, if a UE has a stored version of thisinformation, that is used and applied in the RRC_INACTIVE state. In step108, UE transitions to RRC_INACTIVE.

It should be noted that these are not all steps that are relevant tomake for a UE when transitioning to RRC_INACTIVE. For example, there areaspects related to that the lower level protocols of the UE/UE AccessStratum should communicate with higher layer protocols/UE NON-AccessStratum, that are not illustrated.

The description is applicable in various settings and may includeadditional signaling.

FIG. 2 is a flow diagram illustrating an example method fortransitioning a user equipment to an RRC_INACTIVE state, including anadditional cause value indication. For example, the method illustratessignaling in LTE connected to 5GC, according to some embodiments.

Illustrating a situation when a UE is using LTE as radio network or anyradio network where there could be different solutions to suspend theUE, such as the Release-13 solution (suspend to RRC_IDLE) or theRelease-15 solution (Suspend to RRC_INACTIVE). The radio network nodecan connect to either EPC (an MME+Serving Gateway) or a 5G Core Network(to an AMF+a User Plane Function) or both.

In the situation an LTE UE is receiving an RRC Release message 200, itcan first, in step 202 consider if the Release message includes an RRCInactive Indication (which can be implemented as a release cause e.g.‘suspend-inactive’). If this is not the case, it can consider whetherthere is an indication to suspend to IDLE, this is step 204. In thefigure, it is illustrated as a v1320 cause value, but this cause valuemay be equally applicable also to other standard versions than standardrelease 13. In this situation, it may be called suspend cause v15 orsuspend cause b16 or anything else. It is noted that this is a suspendto idle rather than a suspend to inactive, which was what was determinedin step 202. If there is no suspend indication to IDLE either, then itis concluded in step 210. This may mean that the UE is released to IDLEwithout any need to save any AS. If there was a suspend-to-IDLEindication in step 204, then in step 204, the UE releases to IDLE andstores the AS configuration according to what is standardized for thisprocedure.

If the release to inactive indication in step 202 was included, thenthis indication would, in a similar way as for FIG. 1 and NR, mean thatthe UE should check for a new suspendConfig and read any new potentialsuspendConfig information that relates to how the UE should behave/beconfigured in RRC INACTIVE state in step 206. In step 208, the UEtransitions to RRC_INACTIVE.

In connection to both example procedures above, it has been stated instep 102/202 that the UE should check the release message to determineif it includes a suspend to RRC_INACTIVE indication. Examples of theindication are discussed in further detail below.

In one aspect of the present disclosure, the suspend-to-RRC_INACTIVEindication is a cause value included in the RRC signaling.

Taking the signaling specified for LTE as example, the suspend toRRC_INACTIVE may be added to a set of already existing release causevalues or to include a completely different set of ReleaseCauses forLTE, to use in release messages, when a UE is connected to 5GC. In otherexamples, there could be situations when a UE that connects to 5GCactually has two different suspend mechanisms available for selection.

In some examples, the ReleaseCause-5G is a 2-bit field, (4 values) butit can of course be of different size. Similarly, for NR connected to5GC, a release cause may be included similar to LTE connected to 5GC. Itshould be noted that in both cases above, both for NR and for LTE, therecan of course be other cause values. The technique is applicable topresence of suspend causes, both in situations where there are othercauses or not.

An alternative way of indicating a release to RRC_INACTIVE can,according to another aspect of the present disclosure, be based onpresence or absence of the suspend configuration information. A suspendconfiguration informs the UE how to configure/Behave in RRC_INACTIVEstate and can both be called different things and it can include more orless fields. In some examples, the suspend configuration includesresumeIdentity, pagingCycle, ran-NotificationAreaInfo,periodic-RNAU-timer, and nextHopChainingCount information elements. Apaging cycle is a repetition frequency indicating time instances whenthe UE shall listen for pages from the network. The suspendconfiguration, in this example, further includes the RNA area and atimer for periodic updates of RNAU. The suspend configuration, in thisexample, also includes an NCC NextHopChaining count value which is asecurity-related parameter.

One way of indicating to suspend to RRC_INACTIVE is to include theresumeIdentity in the suspend configuration message. A criteria in e.g.,102/202 above would then be that if the resumeIdentity is included, itis a suspend to RRC_INACTIVE. If the resumeIdentity is not included, andthe suspend configuration is either empty or not present in the releasemessage, then it is a release to RRC_IDLE, or it is a suspend toRRC_IDLE or it is at least not release to RRC_INACTIVE.

According to one aspect of the present disclosure, there is thus thenonly one information element that is mandatory if the suspendconfiguration is included in the release message and that is theresumeIdentity. This means that the rest of the information elements(e.g., pagingCycle, ran-NotificationAreaInfo, periodic-RNAU-timer, andnextHopChainingCount) could be optionally included. If they are notincluded, it could be possible to allow the UE to use previouslyreceived information for any of these information elements without theneed to signal them again.

It should be noted that both options can be equally applicable both forLTE and NR when performing transitions to RRC_INACTIVE and when suchtransition is signaled or triggered by a release message, as describedabove.

In some examples, if an RRC release message (e.g., RRCRelease) includesa suspend configuration field (e.g., suspendConfig, RRC-InactiveConfig),the user equipment stores the following parameters of the suspendconfiguration: resumeIdentity, nextHopChainingCount, PagingCycle andran-NotificationAreaInfo information, if these are not already stored.Delta signalling is applied to resumeIdentity, nextHopChainingCount,PagingCycle and ran-NotificationAreaInfo, if they are stored. If the RRCrelease message does not include the suspend configuration filed, theuser equipment uses the values stored at the UE for the followingparameters of the suspend configuration: resumeIdentity,nextHopChainingCount, PagingCycle and ran-NotificationAreaInfo.

FIG. 3 is a flow diagram illustrating an example method performed by auser equipment for transitioning to an inactive state or an idle state.

At step 302, user equipment that is operating in a connected statereceives an RRC release message. In the present example, the connectedstate is the RRC_CONNECTED state.

At step 304, the user equipment determines, based on an indication inthe RRC release message, whether to suspend the user equipment to aninactive state or an idle state, the indication comprising a presence orabsence a suspend configuration field in the RRC release message. In thepresent example, the inactive state is the RRC_INACTIVE state and theidle state is the RRC_IDLE state.

In some examples, the indication to suspend the user equipment to theinactive state includes the presence of a suspend configuration field inthe RRC release message and the indication to suspend the user equipmentto the idle state comprises the absence of a suspend configuration fieldin the RRC release message. The suspend configuration field may be, forexample, suspendConf or RRC-InactiveConfig. In some examples, thesuspend configuration field indicates a configuration corresponding tothe inactive state.

At step 306, responsive to determining that the indication is to suspendto an inactive state, the user equipment transitions to the inactivestate. For example, the transitioning of the user equipment to theinactive state may be performed during a connection of the userequipment to a 5G core network from a long term evolution (LTE) network.

In some examples, the user equipment applies delta signalingcorresponding to a suspend configuration indicated by the suspendconfiguration field, where the delta signaling includes receivingchanged suspend configuration information indicated by the suspendconfiguration field and accessing unchanged suspend configurationinformation from previously stored suspend configuration information onthe user equipment. In some examples, the suspend configuration includesRAN Notification Area (RNA) information, and delta signalling is appliedto update this RNA information in the suspend configuration.

FIG. 4 is a flow diagram illustrating an example method performed by anetwork node for transitioning a user equipment to an inactive state oran idle state, according to some examples.

At step 402, a network node provides an RRC release message to a userequipment that is operating in a connected state. In the presentexample, the connected state is the RRC_CONNECTED state.

At step 404, the network node triggers, based on an indication in theRRC release message, a suspension of the user equipment to an inactivestate or an idle state, the indication comprising a presence or absencea suspend configuration field in the RRC release message. In the presentexample, the inactive state is the RRC_INACTIVE state and the idle stateis the RRC_IDLE state.

In some examples, the indication to suspend the user equipment to theinactive state includes the presence of a suspend configuration field inthe RRC release message and the indication to suspend the user equipmentto the idle state comprises the absence of a suspend configuration fieldin the RRC release message. The suspend configuration field may be, forexample, suspendConf or RRC-InactiveConfig. In some examples, thesuspend configuration field indicates a configuration corresponding tothe inactive state.

At step 406, the network node causes, responsive to the indication beingto suspend to an inactive state, the user equipment to transition to theinactive state. For example, the transitioning of the user equipment tothe inactive state may be performed during a connection of the userequipment to a 5G core network from a long term evolution (LTE) network.

In some examples, the user equipment applies delta signalingcorresponding to a suspend configuration indicated by the suspendconfiguration field, where the delta signaling includes providingchanged suspend configuration information indicated by the suspendconfiguration field, wherein the user equipment accesses unchangedsuspend configuration information from previously stored suspendconfiguration information on the user equipment. In some examples, thesuspend configuration includes RAN Notification Area (RNA) information,and delta signalling is applied to update this RNA information in thesuspend configuration.

FIG. 5 is a block diagram illustrating an example wireless network.Although the subject matter described herein may be implemented in anyappropriate type of system using any suitable components, theembodiments disclosed herein are described in relation to a wirelessnetwork, such as the example wireless network illustrated in FIG. 5 .For simplicity, the wireless network of FIG. 5 only depicts network 506,network nodes 560 and 560 b, and WDs 510, 510 b, and 510 c. In practice,a wireless network may further include any additional elements suitableto support communication between wireless devices or between a wirelessdevice and another communication device, such as a landline telephone, aservice provider, or any other network node or end device. Of theillustrated components, network node 560 and wireless device (WD) 510are depicted with additional detail. The wireless network may providecommunication and other types of services to one or more wirelessdevices to facilitate the wireless devices' access to and/or use of theservices provided by, or via, the wireless network.

The wireless network may comprise and/or interface with any type ofcommunication, telecommunication, data, cellular, and/or radio networkor other similar type of system. In some embodiments, the wirelessnetwork may be configured to operate according to specific standards orother types of predefined rules or procedures. Thus, particularembodiments of the wireless network may implement communicationstandards, such as Global System for Mobile Communications (GSM),Universal Mobile Telecommunications System (UMTS),

Long Term Evolution (LTE), and/or other suitable 2G, 3G, 4G, or 5Gstandards; wireless local area network (WLAN) standards, such as theIEEE 802.11 standards; and/or any other appropriate wirelesscommunication standard, such as the Worldwide Interoperability forMicrowave Access (WiMax), Bluetooth, Z-Wave and/or ZigBee standards.

Network 506 may comprise one or more backhaul networks, core networks,IP networks, public switched telephone networks (PSTNs), packet datanetworks, optical networks, wide-area networks (WANs), local areanetworks (LANs), wireless local area networks (WLANs), wired networks,wireless networks, metropolitan area networks, and other networks toenable communication between devices.

Network node 560 and WD 510 comprise various components described inmore detail below. These components work together in order to providenetwork node and/or wireless device functionality, such as providingwireless connections in a wireless network. In different embodiments,the wireless network may comprise any number of wired or wirelessnetworks, network nodes, base stations, controllers, wireless devices,relay stations, and/or any other components or systems that mayfacilitate or participate in the communication of data and/or signalswhether via wired or wireless connections.

As used herein, network node refers to equipment capable, configured,arranged and/or operable to communicate directly or indirectly with awireless device and/or with other network nodes or equipment in thewireless network to enable and/or provide wireless access to thewireless device and/or to perform other functions (e.g., administration)in the wireless network. Examples of network nodes include, but are notlimited to, access points (APs) (e.g., radio access points), basestations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs(eNBs) and NR NodeBs (gNBs)). Base stations may be categorized based onthe amount of coverage they provide (or, stated differently, theirtransmit power level) and may then also be referred to as femto basestations, pico base stations, micro base stations, or macro basestations. A base station may be a relay node or a relay donor nodecontrolling a relay. A network node may also include one or more (orall) parts of a distributed radio base station such as centralizeddigital units and/or remote radio units (RRUs), sometimes referred to asRemote Radio Heads (RRHs). Such remote radio units may or may not beintegrated with an antenna as an antenna integrated radio. Parts of adistributed radio base station may also be referred to as nodes in adistributed antenna system (DAS). Yet further examples of network nodesinclude multi-standard radio (MSR) equipment such as MSR BSs, networkcontrollers such as radio network controllers (RNCs) or base stationcontrollers (BSCs), base transceiver stations (BTSs), transmissionpoints, transmission nodes, multi-cell/multicast coordination entities(MCEs), core network nodes (e.g., MSCs, MMEs), O&M nodes, OSS nodes, SONnodes, positioning nodes (e.g., E-SMLCs), and/or MDTs. As anotherexample, a network node may be a virtual network node as described inmore detail below. More generally, however, network nodes may representany suitable device (or group of devices) capable, configured, arranged,and/or operable to enable and/or provide a wireless device with accessto the wireless network or to provide some service to a wireless devicethat has accessed the wireless network.

In FIG. 5 , network node 560 includes processing circuitry 570, devicereadable medium 580, interface 590, auxiliary equipment 584, powersource 586, power circuitry 587, and antenna 562. Although network node560 illustrated in the example wireless network of FIG. 5 may representa device that includes the illustrated combination of hardwarecomponents, other embodiments may comprise network nodes with differentcombinations of components. It is to be understood that a network nodecomprises any suitable combination of hardware and/or software needed toperform the tasks, features, functions and methods disclosed herein.Moreover, while the components of network node 560 are depicted assingle boxes located within a larger box, or nested within multipleboxes, in practice, a network node may comprise multiple differentphysical components that make up a single illustrated component (e.g.,device readable medium 580 may comprise multiple separate hard drives aswell as multiple RAM modules).

Similarly, network node 560 may be composed of multiple physicallyseparate components (e.g., a NodeB component and a RNC component, or aBTS component and a BSC component, etc.), which may each have their ownrespective components. In certain scenarios in which network node 560comprises multiple separate components (e.g., BTS and BSC components),one or more of the separate components may be shared among severalnetwork nodes. For example, a single RNC may control multiple NodeB's.In such a scenario, each unique NodeB and RNC pair, may in someinstances be considered a single separate network node. In someembodiments, network node 560 may be configured to support multipleradio access technologies (RATs). In such embodiments, some componentsmay be duplicated (e.g., separate device readable medium 580 for thedifferent RATs) and some components may be reused (e.g., the sameantenna 562 may be shared by the RATs). Network node 560 may alsoinclude multiple sets of the various illustrated components fordifferent wireless technologies integrated into network node 560, suchas, for example, GSM, WCDMA, LTE, NR, WiFi, or Bluetooth wirelesstechnologies. These wireless technologies may be integrated into thesame or different chip or set of chips and other components withinnetwork node 560.

Processing circuitry 570 is configured to perform any determining,calculating, or similar operations (e.g., certain obtaining operations)described herein as being provided by a network node. These operationsperformed by processing circuitry 570 may include processing informationobtained by processing circuitry 570 by, for example, converting theobtained information into other information, comparing the obtainedinformation or converted information to information stored in thenetwork node, and/or performing one or more operations based on theobtained information or converted information, and as a result of saidprocessing making a determination.

Processing circuitry 570 may comprise a combination of one or more of amicroprocessor, controller, microcontroller, central processing unit,digital signal processor, application-specific integrated circuit, fieldprogrammable gate array, or any other suitable computing device,resource, or combination of hardware, software and/or encoded logicoperable to provide, either alone or in conjunction with other networknode 560 components, such as device readable medium 580, network node560 functionality. For example, processing circuitry 570 may executeinstructions stored in device readable medium 580 or in memory withinprocessing circuitry 570. Such functionality may include providing anyof the various wireless features, functions, or benefits discussedherein. In some embodiments, processing circuitry 570 may include asystem on a chip (SOC).

In some embodiments, processing circuitry 570 may include one or more ofradio frequency (RF) transceiver circuitry 572 and baseband processingcircuitry 574. In some embodiments, radio frequency (RF) transceivercircuitry 572 and baseband processing circuitry 574 may be on separatechips (or sets of chips), boards, or units, such as radio units anddigital units. In alternative embodiments, part or all of RF transceivercircuitry 572 and baseband processing circuitry 574 may be on the samechip or set of chips, boards, or units

In certain embodiments, some or all of the functionality describedherein as being provided by a network node, base station, eNB or othersuch network device may be performed by processing circuitry 570executing instructions stored on device readable medium 580 or memorywithin processing circuitry 570. In alternative embodiments, some or allof the functionality may be provided by processing circuitry 570 withoutexecuting instructions stored on a separate or discrete device readablemedium, such as in a hard-wired manner. In any of those embodiments,whether executing instructions stored on a device readable storagemedium or not, processing circuitry 570 can be configured to perform thedescribed functionality. The benefits provided by such functionality arenot limited to processing circuitry 570 alone or to other components ofnetwork node 560, but are enjoyed by network node 560 as a whole, and/orby end users and the wireless network generally.

Device readable medium 580 may comprise any form of volatile ornon-volatile computer readable memory including, without limitation,persistent storage, solid-state memory, remotely mounted memory,magnetic media, optical media, random access memory (RAM), read-onlymemory (ROM), mass storage media (for example, a hard disk), removablestorage media (for example, a flash drive, a Compact Disk (CD) or aDigital Video Disk (DVD)), and/or any other volatile or non-volatile,non-transitory device readable and/or computer-executable memory devicesthat store information, data, and/or instructions that may be used byprocessing circuitry 570. Device readable medium 580 may store anysuitable instructions, data or information, including a computerprogram, software, an application including one or more of logic, rules,code, tables, etc. and/or other instructions capable of being executedby processing circuitry 570 and, utilized by network node 560. Devicereadable medium 580 may be used to store any calculations made byprocessing circuitry 570 and/or any data received via interface 590. Insome embodiments, processing circuitry 570 and device readable medium580 may be considered to be integrated.

Interface 590 is used in the wired or wireless communication ofsignalling and/or data between network node 560, network 506, and/or WDs510. As illustrated, interface 590 comprises port(s)/terminal(s) 594 tosend and receive data, for example to and from network 506 over a wiredconnection. Interface 590 also includes radio front end circuitry 592that may be coupled to, or in certain embodiments a part of, antenna562. Radio front end circuitry 592 comprises filters 598 and amplifiers596. Radio front end circuitry 592 may be connected to antenna 562 andprocessing circuitry 570. Radio front end circuitry may be configured tocondition signals communicated between antenna 562 and processingcircuitry 570. Radio front end circuitry 592 may receive digital datathat is to be sent out to other network nodes or WDs via a wirelessconnection. Radio front end circuitry 592 may convert the digital datainto a radio signal having the appropriate channel and bandwidthparameters using a combination of filters 598 and/or amplifiers 596. Theradio signal may then be transmitted via antenna 562. Similarly, whenreceiving data, antenna 562 may collect radio signals which are thenconverted into digital data by radio front end circuitry 592. Thedigital data may be passed to processing circuitry 570. In otherembodiments, the interface may comprise different components and/ordifferent combinations of components.

In certain alternative embodiments, network node 560 may not includeseparate radio front end circuitry 592, instead, processing circuitry570 may comprise radio front end circuitry and may be connected toantenna 562 without separate radio front end circuitry 592. Similarly,in some embodiments, all or some of RF transceiver circuitry 572 may beconsidered a part of interface 590. In still other embodiments,interface 590 may include one or more ports or terminals 594, radiofront end circuitry 592, and RF transceiver circuitry 572, as part of aradio unit (not shown), and interface 590 may communicate with basebandprocessing circuitry 574, which is part of a digital unit (not shown).

Antenna 562 may include one or more antennas, or antenna arrays,configured to send and/or receive wireless signals. Antenna 562 may becoupled to radio front end circuitry 590 and may be any type of antennacapable of transmitting and receiving data and/or signals wirelessly. Insome embodiments, antenna 562 may comprise one or more omni-directional,sector or panel antennas operable to transmit/receive radio signalsbetween, for example, 2 GHz and 66 GHz. An omni-directional antenna maybe used to transmit/receive radio signals in any direction, a sectorantenna may be used to transmit/receive radio signals from deviceswithin a particular area, and a panel antenna may be a line of sightantenna used to transmit/receive radio signals in a relatively straightline. In some instances, the use of more than one antenna may bereferred to as MIMO. In certain embodiments, antenna 562 may be separatefrom network node 560 and may be connectable to network node 560 throughan interface or port.

Antenna 562, interface 590, and/or processing circuitry 570 may beconfigured to perform any receiving operations and/or certain obtainingoperations described herein as being performed by a network node. Anyinformation, data and/or signals may be received from a wireless device,another network node and/or any other network equipment. Similarly,antenna 562, interface 590, and/or processing circuitry 570 may beconfigured to perform any transmitting operations described herein asbeing performed by a network node. Any information, data and/or signalsmay be transmitted to a wireless device, another network node and/or anyother network equipment.

Power circuitry 587 may comprise, or be coupled to, power managementcircuitry and is configured to supply the components of network node 560with power for performing the functionality described herein. Powercircuitry 587 may receive power from power source 586. Power source 586and/or power circuitry 587 may be configured to provide power to thevarious components of network node 560 in a form suitable for therespective components (e.g., at a voltage and current level needed foreach respective component). Power source 586 may either be included in,or external to, power circuitry 587 and/or network node 560. Forexample, network node 560 may be connectable to an external power source(e.g., an electricity outlet) via an input circuitry or interface suchas an electrical cable, whereby the external power source supplies powerto power circuitry 587. As a further example, power source 586 maycomprise a source of power in the form of a battery or battery packwhich is connected to, or integrated in, power circuitry 587. Thebattery may provide backup power should the external power source fail.Other types of power sources, such as photovoltaic devices, may also beused.

Alternative embodiments of network node 560 may include additionalcomponents beyond those shown in FIG. 5 that may be responsible forproviding certain aspects of the network node's functionality, includingany of the functionality described herein and/or any functionalitynecessary to support the subject matter described herein. For example,network node 560 may include user interface equipment to allow input ofinformation into network node 560 and to allow output of informationfrom network node 560. This may allow a user to perform diagnostic,maintenance, repair, and other administrative functions for network node560.

As used herein, wireless device (WD) refers to a device capable,configured, arranged and/or operable to communicate wirelessly withnetwork nodes and/or other wireless devices. Unless otherwise noted, theterm WD may be used interchangeably herein with user equipment (UE).Communicating wirelessly may involve transmitting and/or receivingwireless signals using electromagnetic waves, radio waves, infraredwaves, and/or other types of signals suitable for conveying informationthrough air. In some embodiments, a WD may be configured to transmitand/or receive information without direct human interaction. Forinstance, a WD may be designed to transmit information to a network on apredetermined schedule, when triggered by an internal or external event,or in response to requests from the network. Examples of a WD include,but are not limited to, a smart phone, a mobile phone, a cell phone, avoice over IP (VoIP) phone, a wireless local loop phone, a desktopcomputer, a personal digital assistant (PDA), a wireless cameras, agaming console or device, a music storage device, a playback appliance,a wearable terminal device, a wireless endpoint, a mobile station, atablet, a laptop, a laptop-embedded equipment (LEE), a laptop-mountedequipment (LME), a smart device, a wireless customer-premise equipment(CPE). a vehicle-mounted wireless terminal device, etc. A WD may supportdevice-to-device (D2D) communication, for example by implementing a 3GPPstandard for sidelink communication, vehicle-to-vehicle (V2V),vehicle-to-infrastructure (V2I), vehicle-to-everything (V2X) and may inthis case be referred to as a D2D communication device. As yet anotherspecific example, in an Internet of Things (IoT) scenario, a WD mayrepresent a machine or other device that performs monitoring and/ormeasurements, and transmits the results of such monitoring and/ormeasurements to another WD and/or a network node. The WD may in thiscase be a machine-to-machine (M2M) device, which may in a 3GPP contextbe referred to as an MTC device. As one particular example, the WD maybe a UE implementing the 3GPP narrow band internet of things (NB-IoT)standard. Particular examples of such machines or devices are sensors,metering devices such as power meters, industrial machinery, or home orpersonal appliances (e.g. refrigerators, televisions, etc.) personalwearables (e.g., watches, fitness trackers, etc.). In other scenarios, aWD may represent a vehicle or other equipment that is capable ofmonitoring and/or reporting on its operational status or other functionsassociated with its operation. A WD as described above may represent theendpoint of a wireless connection, in which case the device may bereferred to as a wireless terminal. Furthermore, a WD as described abovemay be mobile, in which case it may also be referred to as a mobiledevice or a mobile terminal.

As illustrated, wireless device 510 includes antenna 511, interface 514,processing circuitry 520, device readable medium 530, user interfaceequipment 532, auxiliary equipment 534, power source 536 and powercircuitry 537. WD 510 may include multiple sets of one or more of theillustrated components for different wireless technologies supported byWD 510, such as, for example, GSM, WCDMA, LTE, NR, WiFi, WiMAX, orBluetooth wireless technologies, just to mention a few. These wirelesstechnologies may be integrated into the same or different chips or setof chips as other components within WD 510.

Antenna 511 may include one or more antennas or antenna arrays,configured to send and/or receive wireless signals, and is connected tointerface 514. In certain alternative embodiments, antenna 511 may beseparate from WD 510 and be connectable to WD 510 through an interfaceor port. Antenna 511, interface 514, and/or processing circuitry 520 maybe configured to perform any receiving or transmitting operationsdescribed herein as being performed by a WD. Any information, dataand/or signals may be received from a network node and/or another WD. Insome embodiments, radio front end circuitry and/or antenna 511 may beconsidered an interface.

As illustrated, interface 514 comprises radio front end circuitry 512and antenna 511. Radio front end circuitry 512 comprise one or morefilters 518 and amplifiers 516. Radio front end circuitry 514 isconnected to antenna 511 and processing circuitry 520, and is configuredto condition signals communicated between antenna 511 and processingcircuitry 520. Radio front end circuitry 512 may be coupled to or a partof antenna 511. In some embodiments, WD 510 may not include separateradio front end circuitry 512; rather, processing circuitry 520 maycomprise radio front end circuitry and may be connected to antenna 511.Similarly, in some embodiments, some or all of RF transceiver circuitry522 may be considered a part of interface 514. Radio front end circuitry512 may receive digital data that is to be sent out to other networknodes or WDs via a wireless connection. Radio front end circuitry 512may convert the digital data into a radio signal having the appropriatechannel and bandwidth parameters using a combination of filters 518and/or amplifiers 516. The radio signal may then be transmitted viaantenna 511. Similarly, when receiving data, antenna 511 may collectradio signals which are then converted into digital data by radio frontend circuitry 512. The digital data may be passed to processingcircuitry 520. In other embodiments, the interface may comprisedifferent components and/or different combinations of components.

Processing circuitry 520 may comprise a combination of one or more of amicroprocessor, controller, microcontroller, central processing unit,digital signal processor, application-specific integrated circuit, fieldprogrammable gate array, or any other suitable computing device,resource, or combination of hardware, software, and/or encoded logicoperable to provide, either alone or in conjunction with other WD 510components, such as device readable medium 530, WD 510 functionality.Such functionality may include providing any of the various wirelessfeatures or benefits discussed herein. For example, processing circuitry520 may execute instructions stored in device readable medium 530 or inmemory within processing circuitry 520 to provide the functionalitydisclosed herein.

As illustrated, processing circuitry 520 includes one or more of RFtransceiver circuitry 522, baseband processing circuitry 524, andapplication processing circuitry 526. In other embodiments, theprocessing circuitry may comprise different components and/or differentcombinations of components. In certain embodiments processing circuitry520 of WD 510 may comprise a SOC. In some embodiments, RF transceivercircuitry 522, baseband processing circuitry 524, and applicationprocessing circuitry 526 may be on separate chips or sets of chips. Inalternative embodiments, part or all of baseband processing circuitry524 and application processing circuitry 526 may be combined into onechip or set of chips, and RF transceiver circuitry 522 may be on aseparate chip or set of chips. In still alternative embodiments, part orall of RF transceiver circuitry 522 and baseband processing circuitry524 may be on the same chip or set of chips, and application processingcircuitry 526 may be on a separate chip or set of chips. In yet otheralternative embodiments, part or all of RF transceiver circuitry 522,baseband processing circuitry 524, and application processing circuitry526 may be combined in the same chip or set of chips. In someembodiments, RF transceiver circuitry 522 may be a part of interface514. RF transceiver circuitry 522 may condition RF signals forprocessing circuitry 520.

In certain embodiments, some or all of the functionality describedherein as being performed by a WD may be provided by processingcircuitry 520 executing instructions stored on device readable medium530, which in certain embodiments may be a computer-readable storagemedium. In alternative embodiments, some or all of the functionality maybe provided by processing circuitry 520 without executing instructionsstored on a separate or discrete device readable storage medium, such asin a hard-wired manner. In any of those particular embodiments, whetherexecuting instructions stored on a device readable storage medium ornot, processing circuitry 520 can be configured to perform the describedfunctionality. The benefits provided by such functionality are notlimited to processing circuitry 520 alone or to other components of WD510, but are enjoyed by WD 510 as a whole, and/or by end users and thewireless network generally.

Processing circuitry 520 may be configured to perform any determining,calculating, or similar operations (e.g., certain obtaining operations)described herein as being performed by a WD. These operations, asperformed by processing circuitry 520, may include processinginformation obtained by processing circuitry 520 by, for example,converting the obtained information into other information, comparingthe obtained information or converted information to information storedby WD 510, and/or performing one or more operations based on theobtained information or converted information, and as a result of saidprocessing making a determination.

Device readable medium 530 may be operable to store a computer program,software, an application including one or more of logic, rules, code,tables, etc. and/or other instructions capable of being executed byprocessing circuitry 520. Device readable medium 530 may includecomputer memory (e.g., Random Access Memory (RAM) or Read Only Memory(ROM)), mass storage media (e.g., a hard disk), removable storage media(e.g., a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or anyother volatile or non-volatile, non-transitory device readable and/orcomputer executable memory devices that store information, data, and/orinstructions that may be used by processing circuitry 520. In someembodiments, processing circuitry 520 and device readable medium 530 maybe considered to be integrated.

User interface equipment 532 may provide components that allow for ahuman user to interact with WD 510. Such interaction may be of manyforms, such as visual, audial, tactile, etc. User interface equipment532 may be operable to produce output to the user and to allow the userto provide input to WD 510. The type of interaction may vary dependingon the type of user interface equipment 532 installed in WD 510. Forexample, if WD 510 is a smart phone, the interaction may be via a touchscreen; if WD 510 is a smart meter, the interaction may be through ascreen that provides usage (e.g., the number of gallons used) or aspeaker that provides an audible alert (e.g., if smoke is detected).User interface equipment 532 may include input interfaces, devices andcircuits, and output interfaces, devices and circuits. User interfaceequipment 532 is configured to allow input of information into WD 510,and is connected to processing circuitry 520 to allow processingcircuitry 520 to process the input information. User interface equipment532 may include, for example, a microphone, a proximity or other sensor,keys/buttons, a touch display, one or more cameras, a USB port, or otherinput circuitry. User interface equipment 532 is also configured toallow output of information from WD 510, and to allow processingcircuitry 520 to output information from WD 510. User interfaceequipment 532 may include, for example, a speaker, a display, vibratingcircuitry, a USB port, a headphone interface, or other output circuitry.Using one or more input and output interfaces, devices, and circuits, ofuser interface equipment 532, WD 510 may communicate with end usersand/or the wireless network, and allow them to benefit from thefunctionality described herein.

Auxiliary equipment 534 is operable to provide more specificfunctionality which may not be generally performed by WDs. This maycomprise specialized sensors for doing measurements for variouspurposes, interfaces for additional types of communication such as wiredcommunications etc. The inclusion and type of components of auxiliaryequipment 534 may vary depending on the embodiment and/or scenario.

Power source 536 may, in some embodiments, be in the form of a batteryor battery pack. Other types of power sources, such as an external powersource (e.g., an electricity outlet), photovoltaic devices or powercells, may also be used. WD 510 may further comprise power circuitry 537for delivering power from power source 536 to the various parts of WD510 which need power from power source 536 to carry out anyfunctionality described or indicated herein. Power circuitry 537 may incertain embodiments comprise power management circuitry. Power circuitry537 may additionally or alternatively be operable to receive power froman external power source; in which case WD 510 may be connectable to theexternal power source (such as an electricity outlet) via inputcircuitry or an interface such as an electrical power cable. Powercircuitry 537 may also in certain embodiments be operable to deliverpower from an external power source to power source 536. This may be,for example, for the charging of power source 536. Power circuitry 537may perform any formatting, converting, or other modification to thepower from power source 536 to make the power suitable for therespective components of WD 510 to which power is supplied.

Any appropriate steps, methods, features, functions, or benefitsdisclosed herein may be performed through one or more functional unitsor modules of one or more virtual apparatuses. Each virtual apparatusmay comprise a number of these functional units. These functional unitsmay be implemented via processing circuitry, which may include one ormore microprocessor or microcontrollers, as well as other digitalhardware, which may include digital signal processors (DSPs),special-purpose digital logic, and the like. The processing circuitrymay be configured to execute program code stored in memory, which mayinclude one or several types of memory such as read-only memory (ROM),random-access memory (RAM), cache memory, flash memory devices, opticalstorage devices, etc. Program code stored in memory includes programinstructions for executing one or more telecommunications and/or datacommunications protocols as well as instructions for carrying out one ormore of the techniques described herein. In some implementations, theprocessing circuitry may be used to cause the respective functional unitto perform corresponding functions according one or more embodiments ofthe present disclosure.

The invention claimed is:
 1. A method performed by a user equipment (UE), the method comprising: receiving a radio resource control (RRC) release message from a network node; determining that the RRC release message includes a suspend configuration field; applying delta signalling corresponding to a suspend configuration indicated by the suspend configuration field; and transitioning the user equipment to an inactive state.
 2. The method of claim 1, wherein the suspend configuration field indicates a configuration corresponding to the inactive state.
 3. The method of claim 1, wherein applying delta signalling comprises: receiving changed suspend configuration information indicated by the suspend configuration field; and accessing unchanged suspend configuration information from previously stored suspend configuration information on the user equipment.
 4. The method of claim 1, wherein the suspend configuration includes RAN Notification Area (RNA) information.
 5. The method of claim 1, wherein the delta signalling is applied to update RAN Notification Area (RNA) information in the suspend configuration.
 6. The method of claim 1, wherein the transitioning of the user equipment to the inactive state is performed during a connection of the user equipment to a 5G core network from a long term evolution (LTE) network.
 7. The method of claim 1, wherein the RRC release message is received while user equipment is operating in a connected state.
 8. A non-transitory computer readable medium storing computer readable program code executable by processing circuitry of a user equipment to perform operations comprising: receiving a radio resource control (RRC) release message from a network node; determining that the RRC release message includes a suspend configuration field; applying delta signalling corresponding to a suspend configuration indicated by the suspend configuration field; and transitioning the user equipment to an inactive state.
 9. The non-transitory computer readable medium of claim 8, wherein the suspend configuration field indicates a configuration corresponding to the inactive state.
 10. The non-transitory computer readable medium of claim 8, wherein applying delta signalling comprises: receiving changed suspend configuration information indicated by the suspend configuration field; and accessing unchanged suspend configuration information from previously stored suspend configuration information on the user equipment.
 11. The non-transitory computer readable medium of claim 8, wherein the suspend configuration includes RAN Notification Area (RNA) information.
 12. The non-transitory computer readable medium of claim 8, wherein the delta signalling is applied to update RAN Notification Area (RNA) information in the suspend configuration.
 13. The non-transitory computer readable medium of claim 8, wherein the transitioning of the user equipment to the inactive state is performed during a connection of the user equipment to a 5G core network from a long term evolution (LTE) network.
 14. The non-transitory computer readable medium of claim 8, wherein the RRC release message is received while user equipment is operating in a connected state.
 15. A user equipment comprising: a non-transitory memory; and processing circuitry coupled to the non-transitory memory and configured to read instructions from the non-transitory memory to perform operations comprising: receiving a radio resource control (RRC) release message from a network node; determining that the RRC release message includes a suspend configuration field; applying delta signalling corresponding to a suspend configuration indicated by the suspend configuration field; and transitioning the user equipment to an inactive state.
 16. The user equipment of claim 15, wherein the suspend configuration field indicates a configuration corresponding to the inactive state.
 17. The user equipment of claim 15, wherein applying delta signalling comprises: receiving changed suspend configuration information indicated by the suspend configuration field; and accessing unchanged suspend configuration information from previously stored suspend configuration information on the user equipment.
 18. The user equipment of claim 15, wherein the suspend configuration includes RAN Notification Area (RNA) information.
 19. The user equipment of claim 15, wherein the delta signalling is applied to update RAN Notification Area (RNA) information in the suspend configuration.
 20. The user equipment of claim 15, wherein the RRC release message is received while user equipment is operating in a connected state. 